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War with Toyota

Discussion in 'Gen 2 Prius Main Forum' started by jessewilson, Jul 29, 2010.

  1. DetPrius

    DetPrius Active Member

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    Yeah, I'm reading the same thread, and wondering if you could disconnect the battery from the Prius and then connect it to the donor car with its engine running for 10 minutes, and then disconnect the donor car, reconnect to the Prius and away you go, or as you suggest, put it on a battery charger if one is available.
     
  2. SW03ES

    SW03ES Senior Member

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    :deadhorse:
     
  3. Batter up

    Batter up New Member

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    Hello, Dad here.
    I am overwhelmed by the thoughtful discussion and debate taking place in respect to my sons original posting. I have learned much about the electrical system in a Prius and would like to thank all of you who have made the eeffort to comment both in support with my problem and also to those of you who have given me a slap on the side of the head for being ignorant of the complexity of boosting a Prius.
    Here is what I have learned from my experiance and your excellent comments:
    1.Don't boost a Prius under any circumstance. Call the dealer or the Auto Assn, for a tow, NOT a boost.
    2.Buy and expect to use a trickle charger.
    3.Don't count on the dealer for a heads up in advance of a problem. I had my Prius into the dealer twice with battery related concerns. They did not read me the riot act, but simply advised that a new battery would be required in the near future.
    4. 12v battery problems with the Prius are common.
    Again, thanks to all who have helped me understand my Prius. Hopefully other Prius owners have benefited from this exchange. In a perfect world even Toyota would take notice of this type of problem and do more to safeguard the cars electrical system from "Ordinary Joe" owners like me!
     
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  4. snead_c

    snead_c Jam Ma's Car

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    Welcome Dad. Mighty big of you to come on board and offer thanks for all the comments. No doubt you can tell that this site is loaded with valuable info as well as strong opinions. :welcome:

    I believe I'm speaking for all PCers when I say "We're sorry for your painful lesson." :(
     
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  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Dad,

    Thanks for checking in. Please provide the list of damaged parts besides the inverter.

    Also, did you decide to have the car repaired by the dealer?
     
  6. ronhowell

    ronhowell Active Member

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    So you are saying, Patrick, that if you are either re-charging or jump starting the Prius (mine is a 2008) using correct polarity (+ve to +ve; -ve to -ve) connections from under the hood, a voltage and/or current oversupply is unlikely due to the presence of the DC/DC converter in the circuit, which normally supplies the OEM 12V battery from the HV battery pack, at around 14.1 - 14.4V (if my ScangaugeII output is to be believed) through the DC/DC converter.

    Also, if you are in a situation where you want to recharge the 12V battery via, for instance, a home charger similar to the one I have operating from a 120V supply, would the use of the 12V/15 Amp output present a problem, as opposed to the alternate 12V/2 Amp output available from the same charger?

    At what voltage level degradation does the 12V system start to present problems? My vehicle will be coming up on 3 years soon, so I'd like to get ahead of potential hiccups!
     
  7. ronhowell

    ronhowell Active Member

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    Re: 12V battery system on 2008 Prius.

    deleted
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Ron,

    I would say that a voltage or current oversupply is unlikely but not impossible, if correct polarity is observed. This is not due to the presence of the DC/DC converter, but rather because the Prius 12V battery will tend to absorb a voltage oversupply.

    Toyota recommends that when the 12V battery is being charged, that the battery should be disconnected and physically removed from the car first. Presumably this recommendation is intended to eliminate any possibility of damaging the vehicle electronics or the vehicle itself, in the event that the battery has a problem during the charging process. I doubt that very many owners will observe this recommendation.

    Regarding charging the 12V battery with the 10A or higher position on the charger, you will find a warning label on the battery to the effect that no more than ~4A charging current should be used. This is why I suggest using the 2A position. If you use the higher position due to impatience, it would be at your own risk.

    Since you live in an area with moderate climate, as long as your car gets reasonable use (10K miles or more per year) and you don't make a habit of leaving cabin lights on etc. to discharge the battery, then I would say you should not have to worry about the 12V battery until after 5-6 years of service. At that point you may want to replace the battery as a preventive move, to minimize unscheduled downtime.
     
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  9. edthefox5

    edthefox5 Senior Member

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  10. tedjohnson

    tedjohnson Member

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    There is something about the 12 volt batteries in hybrids that seems to shorten their lives. Maybe they never see any serious discharge, not sure. But in my 2000 Insight the OEM battery failed (shorted cell) at the 3 year old age. I would plan on replacing the 12 volt battery every 3 years routinely on any hybrid. A disabled 12 volt battery might get you started and then fail on the road somewhere. Mine did.I agree the safest way is to remove the battery try to recharge and reinstall it after checking the state of charge.
     
  11. qbee42

    qbee42 My other car is a boat

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    You can't have it both ways. If the battery is a dead short, it will absorb any reasonable over-voltage situation. If the battery is not seriously depleted, you won't have a big inrush of current.

    Tom
     
  12. edthefox5

    edthefox5 Senior Member

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    Maybe I can. Your assuming a fixed never changing load or should I say a smooth slew rate of charging. Thats not the case,. You have instant max load quickly followed by a normal load. An overvolt would happen if a seriously depleted Prius battery was hooked to a car and that inital inrush would pull max current out of the donor battery and pull the donor battery volt low. The donor alternator would then regulate maximum voltage and current out of the alternator to keep that donor battery at 13.8 under maximum load. The overvolt happens when the initial inrush being consumed by the dead prius battery levels out and the donor alternator already at max cannot track the battery voltage back where it belongs fast enough. This all happens in about a second. Most car alternators cannot track that instantaneous load.

    I'm not saying 10 volts over rate but maybe 2 or 3 volts. And the battery would have nothing to do with lessening it. Its all about how fast the regulator can track it. And sometimes that donor car's alternator gets damaged too.

    Its the same phenomenon that happens to switch mode power supplies when you brown them out. The great destroyer of new tv's.

    This situation is exacerbated by a poorly performing donor alternator regulator.

    But I don't think its a overvolt issue that's causing the issue on the Prius jump. Its that big current inrush across the keep alive circuit.
     
  13. qbee42

    qbee42 My other car is a boat

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    True enough, but only if the slew rate has a very fast rise. It would take a fairly freakish set of circumstances to cause the battery voltage of the charging battery to jump high in less than a second. I'm not saying it can't happen, but this is a very contrived scenario. The voltage on a charging lead-acid battery stays flat during the initial charge when the system is current limited, then begins a gentle ramp as the surface of the plates fully charge. Deeper charge takes quite a bit of time, allowing plenty of time for the regulator to track.

    I can think of many freakish situations where inductive kick, bad regulators, or failing components can cause out of spec voltages. Just because they can happen doesn't mean they are likely to happen.

    Tom
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I have 6 gauge jumper cables, 16 feet long. The resistance of 32 feet of 6 gauge copper wire is ~0.013 ohm.
    American Wire Gauge, AWG Cable Size Description for Copper Wire Cable

    Suppose you have 100A of current flow during this inrush that Ed is concerned about. Using my jumper cables, the resistance will produce a voltage drop of 1.3V, which will absorb around half of the excess voltage that Ed has speculated might occur.

    Regarding the current inrush, that is only going through the 12V battery. The ECUs that remain powered up just see voltage fluctuations on the 12V bus.

    I'd still be interested in seeing a post that provides evidence of a damaged Prius ECU.
     
  15. Batter up

    Batter up New Member

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    Hi Patrick.... Thanks again to all of you who chipped in to provide good information on how to keep my Prius on the road.

    Here is the conclusion to my saga.... Yes the Dealership repaired the Prius. Total charges were around $6500 CDN. This included the inverter $4271., fusable link $115.71 and Labor $593.95.

    In addition they deemed that the rear hatch lock was defective @$454.86 and of course the battery @219.14.

    In the end, the dealership showed very little compassion but ended up with a very juicy repair account.

    Unfortunately they have completely lost my good will and just last week I assisted my daughter in her purchase of a new Mazda 3. This would have been a Matrix purchase and we likely would not even have checked out the Mazda dealership, had we as a family not soured on all things Toyota.
     
  16. SW03ES

    SW03ES Senior Member

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  17. UGC

    UGC Member

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    Here's an Idea; Think preventive maintenance...

    Install a battery disconnect switch now, while your prius is running fine with no issues.

    like this under the hood:http://www.amazon.com/dp/product/B0017101BE?tag=priuschatcom-20
    Then, if you ever need a jump, TURN OFF the switch and hook up your cables, let the battery charge for about ten minutes, unhook jumper cables, TURN ON the battery disconnect switch, start the car, and drive to nearest dealership and fix your problem.

    This would keep ALL the Prius electronic circuits out of harms way durning a "JUMP/RECHARGE" of the battery.

    Just an Idea.
     
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That's a reasonable idea. I have another: replace the 12V battery before it fails, rather than trying to eke out the last dregs of service life from it.
     
  19. andyprius

    andyprius Senior Member

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    What is the hook-up under the hood? They have these at Harbor Freight for $6-8. not $30 with shipping. I just installed a simple toggle swich between the ground and negative terminal. Cost: $1.50 Works fine.
     
  20. UGC

    UGC Member

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    Install whatever switch you want. I'm not trying to sell you the switch. NOTE: The cut off switch you install needs to be rated to handle the full load of the vehicle (the full draw on the battery, volts and amps), or; 1) You might catch fire 2) On the side of the road because the contacts of the switch burned out.

    You want the switch located close to where you would hookup the jumper cables (easy to get to/and work with).

    One poster said just keep installing new batteries before they fail. That is great advice. and I would say do that to, but....that is still no guarantee that you would never need a jump.

    EDIT: This is only advice. It will seperate your cars electronics from the battery during a jump and make you at less risk of expensive repairs because of a "jump" not performed correctly.